Approximate Boundary Conditions for Index Mismatched Diffuse-Diffuse Interfaces

Since the application of the boundary condition for diffuse-diffuse interfaces with index mismatch is difficult, an approximation that yields very accurate values for biological media is found. The results obtained with the approximate boundary condition are compared with exact numerical results, showing the importance of this effect, and the quantitative errors committed when neglecting this term are presented. This approximation can be easily introduced in analytical models, and a study of its limit of validity is shown.